题目
Whichof the following tests of a hypothesis concerning the population mean is mostappropriate?
选项
A.A z-test if the population variance is unknown and the sample is small
B.A z-test if the population is normally distributed with a known variance
C.A t-test if the population is non-normally distributed with unknown variance and a small sample
答案
B
解析
： B is correct. The z-test istheoretically the correct test to use in those limited cases when testing thepopulation mean of a normally distributed population with known variance. ： B正确。 理论上，有限情况下，z检验是：检验已知方差的正态分布总体均值时的正确检验，